Method of and apparatus for cooling electrical generators and motors.



F. G. BAUM.

METHOD OF AND APPARATUS FOR COOLING ELECTRICAL GENERATORS AND MOTORS.

APPLICATION FILED SEPT. 7, 1910 987,536, I Patented Mar.21, 1911.

2 SHEETS-SHEET 1,

P. G. BAU

METHOD OF AND APPARATUS FOR COOLING ELE G ENERATORS AND MOTORS.

APPLICATION FILED SEPT. 7,

987,536. Patented Mar.21, 1911.

2 SHEETS-SHEBT 2.

wit namely (311 vs M10;

' 1s hence very inefficient; since the air cannot period of the year, the air then being generthe laminations coming in contact with the UNITED STATES PATENT OFFICE} FRANK GEORGE BAUH, OF SAN FRANCISCO, CALIFORNIA I union or AND APPARATUS FOR coomne ELECTRICAL ennnrmroas AND morons.

Specification of Letters Patent.

Patented Mar. 21, 1911.

Application filed September 7, 1910. Serial No. 580,816.'

To all whom it may concern:

Be it known that I, FRANK G. BAUM, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented certain new and useful Improvements in Methods of and Apparatus for Cooling Electrical Generators and Motors, of which the following is a full, clear, and exact description.

This invention relates to a method and apparatus for cooling armatures of electrical generators and motors, and the like, and has for one of its objects the provision of apparatus adapted for this purpose which can be cheaply constructed, is economical in operation, and much more eflicient than de vices of this character as heretofore made.

As usually constructed, the revolving element in a generator or motor is so arranged that it will drive some air through the field and armature vent holes. In this case air is taken in having a temperature substantially that of the surrounding atmosphere; and there is very little efiective pressure whereby to force it through the vent holes to properly cool the machine. This method be roperly driven through all of the holes; and by reason of the fact thatthe air is not at the right temperature to take up heat, this being especially the case in the warm ally quite hot. Further, the air carries but little moisture in summer, particularly in certain localities, and the amount of heat which the air can take up depends largely upon the moisture which it carries.

The herein described invention aims to materially reduce the temperature of electric current generating apparatus and the like, preventing such apparatus from running hot and thereby adapting said apparatu s'to carry a higher load.

The principal objects of my invention are therefore, first, to force air at any desired pressure through all of the vent holes of armature coils, and finally with the field coils; and second, to reduce the temperature of the supplied air below the temperature of the surrounding air and to add water to the supplied air thereby adapting it to more readily take up heat.

Other objects of my invention will be I 'method. Fig. 2 is a section taken through the'cooling apparatus; and Fig. 3 is a section taken through a portion of the arma, ture to show the path of the air there-' through.

Like characters of reference have been used to designate like parts throughout the several views.

The generator has been broadly designated 1, being driven by any suitable prime mover 2.

In this exemplification of my invention, the armature 3 is stationary and the field 4 rotatable therein, being mounted on shaft 5 in the usual manner. The armature laminations Gare provided with the usual vents 7 therethrough and in applying my apparatus to generators of this type, as usually constructed, I prefer to close the regular vent holes 8 by suitable covers 9, utilizing the space in the portion 10 of the armature casing adjacent the peripheral surface of the laminations as a conduit or receptacle wherein air from the blower may be held under pressure; such conduit being designated 11. This air space or conduit is connected to an air main 12 in any approved manner, a suitable gate 13 being positioned in the air inlet 14 which connects the conduit 11 and air main 12. The air main 12 may extend along a line of generators so that air under pressure may be supplied thereto and suitable gates may be disposed in this main to afford tion tube 18 thereof exten s into a casing which I have broadly designated 19; This casing is formed by covering a suitable wooden or other frame 20 with coarse cloth, burlap or other suitable material 21 on one or more sides thereof, the remainder of the casing being covered with wood, sheet metal or other material22. The casing 19 should preferably be of relatively considerable size, and the burlap or cloth covering thereof is adapted-to be ke t eont-inuously ma. by

dition to the nozzles 23 which deliver upon" the outer surfaces of the reticulated covering, I also introduce a nozzle 25 directlyinto the body of the receptacle or casing 19, the entrance to which is also covered by cloth, or the like 26, this latter nozzle being directed toward the opening of the pipe 18 so that very fine particles of moisture may be entrained by the air rushing into the said pipe. By thus continuously moistening the reticulated surface through which the air is forced to pass, such air is induced to absorb moisture practically to the point of saturation; while the nozzle 25 inside of the casing adds moisture in the form of minute particles to the already saturated air, such particles being entrained thereby and earned along in suspension. This air is forced through the blower and is delivered to the conduit 11 which extends around the armature or like part; and as it approaches the heated parts of the machine, more particularly immediately after it has entered the said conduit, the suspended particles will. beevaporated and in evaporating will of course take up heat.

Assuming now that the air be delivered to the blower under the most adverse conditions, to wit, in summer when the temperature of the air may approximate 102 de ees 'F.; at this temperature a cubic foot 0 air -saturated with moisture will carry .00299 pounds of water. At a temperature of 152, which under such conditions might be the temperature in the vicinity of the armature,

the same cubic foot of air will, when saturated, carry .0107 pounds of water. The difference between the water carried by the air at 102 and that carried by the air at 152, is hence approximately .0077 pounds per cubic foot of air. pounds of water canbe added to the saturated air at 102 and such water can'be carried to the machine entrained in the air. If the temperature of the machine is, let us say, 152, all the water so'held in suspension will be evaporated; the temperature of the air being raised to 152, and the air being again completely saturated at that tem perature. The amount of heat per pound of air which the air with the water in suspension in raising 50 F. would absorb, would be :.78 of a heat unit per cubic foot'of such air, and 7.45 heat units for the water in suspension at 102, such water being evaporated at 152. The heat units absorbed by the water are therefore nearly ten times the heat units absorbed by the air in raising this 50.

In other words, .0077

heat units from a heated generator is therefore relatively enormousials merely partially saturated air K. W. gene erato'r may have a heat loss of 250 K. W., or about 250XM12= heat units r hour. Assumi that each cubic foot 0 air and added moisture can take u four 'heat' units, there would be req about 213,000 cubic feet of air per hour, or approximately .3550 cubic feet of. air per minute. The air would, in this case, be only .half saturated; but it is. well to be on the safe side, and for this reason I prefer to increase the quantity of air two or three times, and reduce the quantity of water in suspension correspondingly which gives the same result and which eliminates any possible danger of precipitatin moisture in the generator. As a result 0 this, a lar kilowatt capacity is gained for but 9. sm 1 expenditure of power.

Another way of considerin air be supplied at a temperature of 102, and that this 'air be caused to evaporate water 'so that it will have a 10% saturation; each cubic foot will then about .0003 pounds of water. The British thermal units absorbed by this amountof water would be .0003X996, or about .29 heat units.

Tlhe advantage of usingmoisture to take up the obtained is as follows: Assuming that dry humidity up to 60, the resultant drop temperature will be the same. It is of the utmost im should be entrained, as otherwise moisture mi htbe de coi s. As a result of raw' the air ra idly through the coarse wet/ti t? cloths, 1711151 are .kept wet by the fine spray, the air evap orates a large portion of this moisture and the drop in temperature in this air from this source is also very material.

Having described my invention, what I- claim,'is: 1

1. A method of cooling electric generators which consists in a current of air in a predetermined direction,.saturating such current of air with moisture, injecting a predetermined amount of. water inthe form of particles into said air current whereby such water may be entrained therein, supplying said air under ressure to a. conduit disposed adjacent to an heated by the parts to be cooled, completely evapportanoe of that but certain definite amoun't'sof water tedu nandinjurethe 987,536 a orating the said entrained particles of water heat emittin before said particles emerge from said condisposed sui ciently adjacent said conduit duit by the heat of the parts to be cooled to completely evaporate said predetermined and thereafter conducting the air so freed excess of vaporizable material While the from entrained moisture past the said parts. latter is Within the confines of the conduit, 2. In combination, a conduit, a device for said conduit having the exhaust opening forcing a cooling medium through said conthereof arranged to deliver the dry cooling duvit, apparatus for introducing vaporizable medium past the said parts. material into a cooling medium whereby to f In Witness whereof, I subscribe my sig saturate said medium and thereby reduce 1 nature, in the presenceof two witnesses FRANK GEORGE BAUM.

parts which are to be cooled the temperature thereof, spray-forming ap- 4 I paratus for introducing into the mass of saturated medium a predetermined excess, \Vitnesses: of said material 1n the form of mmute LARS JORGENSEN, 15 particles, and an electric appliance having N. M. PORTER. 

